1. Field of the Invention
The present invention relates to drains for swimming pools, spas and whirlpool baths and, more particularly, to a drain for reducing the likelihood of entrapment of a person's hair and body parts.
2. Description of the Related Art
Typically, a suction outlet or drain used in a pool or spa is located at the bottom or in a wall of such pool, spa or bath. The drain provides an outflow of water into a suction line connected to a suction pump. A debris trap or the like may be disposed between the suction line and the pump to collect large sized debris. Usually, the outflow from the pump passes through a filter and is ultimately returned to the pool, spa or bath.
The suction attendant the drain may be significant, which poses a danger to a user of or a bather in the pool, spa or bath. Should the drain be covered by a body part, the force of the suction acting on such body part may be sufficient to prevent the person from extricating himself/herself and drowning may occur or significant injury may result. Often, the hair of a bather may be drawn into the drain and become tangled about elements of the drain or wrapped about itself to the extent that extrication may be impossible. Again, the consequences may include drowning. Because of these hazards to users of a pool, spa or bath, various efforts have been undertaken to preclude such entrapment.
In 1923, Booraem disclosed in U.S. Pat. No. 1,454,310 a rudimentary grating covering a drain for the purpose of protecting a bather from the hazards associated with limb entrapment. The grate also served the function of screening debris to keep it out of the suction line and other downstream elements.
As spas and whirlpool bathtubs became more widely used, the bathers were usually in much closer proximity to an active drain for longer periods of time. This resulted in hair entrapment injuries as well as drowning. The increase of injuries of this type and related drownings dictated the evolvement of drains with more effective features to prevent hair entrapment. A resulting improvement of the drain was that of using a cover with small orifices to reduce the likelihood of hair passage therethrough. However, when a large volume of hair was proximate the apertures, the resulting differential pressure was often sufficient to draw hairs through the small orifices. After the hair passed through the orifices, it often wrapped about itself and effectively prevented withdrawal of the hair. An improvement to the use of such small orifices is disclosed in a 1998 patent to Perry, Et al., U.S. Pat. No. 5,799,399 which taught the use of internal guide vanes to reduce turbulent flow of the water and thereby reduce tangling of hair passing through the orifices. Guide vanes reduced the likelihood of hair entanglement, but the problem was still present, especially when the orifices were essentially covered by hair.
Another approach to prevent hair entanglement is disclosed by Nelson in U.S. Pat. No. 5,978,981 wherein a plurality of elongated flow channels are provided which are of sufficient length that hair cannot reach the end of the channels where it might tangle. Since some bathers have very long hair, the channels had to be of extended length to prevent entanglement of such hair. This necessitated a large drain cover which was difficult to manufacture. It also required significant space to accommodate the channels which space was often impractical or impossible in many typical locations.
U.S. Pat. No. 6,088,842, issued to Barnett discloses another approach by providing a plurality of protrusions positioned to form a grating arrangement with a single opening. The protrusions are shaped to facilitate the removal of tangled hair. This apparatus may work well for limited volumes of hair exposed to limited flow rates. However, most modern suction pumps have significant flow capabilities well above the level required to create turbulent flow behind the protrusions. Such turbulence can and will tangle hair making it difficult or impossible to pull the hair back through the openings.
To address the hazard of entrapment a body part due to the pressure differential across a drain cover when it is blocked by the body part, certain standards have been promulgated by the National Spa and Pool Institute. In particular, such standards prohibit the use of a single point suction on small drain covers that can be completely blocked by a bather. The most widespread solution and compliance with the standards involves the use of two drains in fluid communication with one another through a common suction line. When such arrangement is used, complete blockage of one drain will not result in significant pressure differential across the blocked drain as the suction force is relieved by flow through the second drain. Thus, removal of the body part from the affected drain was usually possible.
While single-point suction is prohibited by most construction standards and codes, such is not always the case. Even when it is, installers are frequently unaware of the requirement or simply feel that it is not necessary based on their personal experience. It is therefore of import to provide a suction outlet or drain which self-limits the water flow and localized velocities to a level below that required to entangle or entrap hair. Additionally, it would be beneficial to minimize the amount of differential pressure that may come in contact with a bather by dispersing the inlet orifices over a large area to reduce the likelihood of complete blockage.
It is therefore a primary object of the present invention to provide a drain for a pool, a spa or a whirlpool bath that reduces the likelihood of entry of hair through the inlet orifices.
Another object of the present invention is to provide a drain for a pool, spa or bath which includes secondary inlet orifices to prevent a pressure differential across the drain in the event of partial or complete blockage of the primary inlet orifices.
Still another object of the present invention is to provide inlet orifices having mechanical features for reducing the likelihood of passage of hair therethrough.
Yet another object of the present invention is to provide a drain for a pool, spa or bath that reduces the likelihood of entanglement of any hair that may inadvertently enter through the inlet orifices.
A further object of the present invention is to provide a drain for a pool, spa or bath that has a limited water flow rate through each of a plurality of inlet orifices relative to the water flow rate of the suction line connected to the drain.
A yet further object of the present invention is to provide passageways extending from inlet orifices to segregate any hair entering therein and prevent entanglement.
A still further object of the present invention is to provide a method for reducing the likelihood of entrapment of hair in a drain for a pool, spa or whirlpool bath.
These and other objects of the present invention to those skilled in the art as the description thereof proceeds.